It was like I was back in my first days of programming more than 10 years ago; I tried to implement CardSpaces on a sample page and nothing would work like it should. I click a button and the form submits without loading the CardSpaces selector. I even copied the HTML from a working sample into my own, and STILL no CardSpaces love.
HTTPS…
Yeah, without HTTPS the CardSpaces UI will not show at all. Honestly guys, would adding a “The CardSpaces internet explorer plugin could not initialize because the connection was not secured” message have been that hard?
Even worse, my dodgy OpenSSL-generated certificate does not appear to be good enough:

Now, I know there is a debug mode for developing a relying party without having to buy an IIS cert for my development machine. There IS a debug mode, right Microsoft? RIGHT!?
Have you tried configuring the issuer certificate for your ‘dodgy OpenSSL’ sertificate as a trusted root certification authority certificate in IE?